How to add a new revenue line on income statement?

Good afternoon, @Arm Alb.

How's your day going so far? I hope all is well. 

Do you mean to create a new Revenue (Income, Sales) account in your Chart of Accounts? If so, this can be done with the instructions below:

Creating a New Ledger Account:

1. From QuickBooks Online, click the Gear icon then choose Chart of Accounts.
2. Click New. Under Account Type, select Income or Other Income.
3. Browse and click on a Detail Type that most closely matches the new account's purpose.
4. Enter a Name for the account then click Save and close.

We also offer a guide on creating new ledger accounts here for your convenience.

Don't hesitate to let me know if there is anything else I can assist you with. I'm always happy to help out. Take care and have a wonderful day!